1. Field of the Invention
The present invention relates in general to the field of information handling system power management, and more particularly to a method and system for information handling system component power management sequencing.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
As the number of information handling systems in use by individuals, businesses and governments have increased, power consumption by information handling systems has also increased. Often, information handling systems are left on in a fully operational state even though their users are not actively performing functions or otherwise using the information handling systems. For instance, users frequently leave information handling systems on when the users are absent, such as during lunch or other breaks or even at the end of the business day. To reduce wasted power consumption that results from running information handling systems when those systems are not being actively used, government has encouraged the adoption of a number of power management standards that automatically bring information handling systems to reduced power states during periods of non-use. For instance, information handling system components are shut down after a period of time in which no user inputs are detected and automatically returned to an operational state when a user makes an input or activates the power button.
The power consumption standards demanded by government specify an amount of allowable power consumption in a power down state that is very small. However, as information handling system components have grown more powerful these components tend to consume greater amounts of power so greater numbers of components generally must be powered down in order to meet the power consumption standards. Typically, power management is accomplished by firmware located in the BIOS that selects components to power down so that power consumption in a power down inactive state (S5) is less than one watt, substantially less than power consumption in the active state (S0). The power management firmware in the BIOS also typically handles power up from the inactive state to the active state, such as when a user initiates use of the information handling system. In very low power consumption states, the BIOS itself is typically powered down so that power up generally occurs when the user activates the power switch to apply power to the BIOS and power management firmware. One difficulty with performing power management from the BIOS is that some components should have power before or simultaneously with the BIOS. For instance, network interface controllers (NICs) generally should have power before the BIOS performs a PCI reset during recovery from the power save mode. Thus, information handling systems that have NICs which consume greater than an allowable power consumption of an inactive state will fail to meet the power consumption standard where power management is performed by BIOS firmware.